Ten years' worth of Earth's wetness and aridity, as observed from space
While the effects of droughts reveal themselves in the short term through arid fields and withered riverbeds, their ongoing impact reveals itself most readily below the crust of the Earth. Ground water, both right under the surface and deep underneath it, suggests how months and years of dryness will affect us in the long run.
In the video above, NASA satellites capture these effects in color-coded -- and fairly alarming -- form. Spooling out are ten years' worth of data, provided by the Gravity Recovery and Climate Experiment (GRACE) science team and rendered visually by Chris Poulsen of the National Drought Mitigation Center.
For a more detailed take on the effects of the 2012 drought, in particular, below are images courtesy of NASA's Earth Observatory, their data captured a few days ago. As the Earth Observatory explains: "The top map shows moisture content in the top 2 centimeters (0.8 inches) of surface soil; the middle map depicts moisture in the 'root zone,' or the top meter (39 inches) of soil; and the third map shows groundwater in aquifers." And the maps are longitudinal; scientists compared the wetness of each layer to the mid-September average for each year between 1948 and 2009, and then represented the relational number in the image. So the darkest red regions, for example, represent dry conditions that should occur only about 2 percent of the time -- or once every 50 years.
The images below represent pretty much this moment in 2012. And they are colored in, you'll notice, with a good amount of deep, dark red.